Stormwater Pollution Prevention

Flooded neighborhood street with cars under water

Stormwater is rain or snow that "runs off" across the land instead of seeping into the ground. Runoff is increased from surfaces which do not absorb water such as roads, parking lots, and roofs. The storm drains along streets and curbs allow rain and melting snow to move from the streets into a network of manmade pipes and natural channels ending up in our streams and lakes.

Stormwater is not treated before it ends up in a stream, lake, or river. Stormwater replenishes our sources of drinking water – lakes, streams and groundwater. Clean stormwater is vital to our quality of life and to the quality of our drinking and recreational waters.

Everyone in Johnson County, including you, has an important role to play in keeping our stormwater and ultimately local water resources free of harmful pollutants. By playing your part you are helping Johnson County remain a sustainable community with a plentiful and safe water supply.

Water Quality

The Storm Drainage System and how it works

The storm drainage system comprises of many storm drains, pipes and channels. Storm drains are openings in streets or curbs that are sometimes covered with metal grates. The storm drains allow rain and melting snow to move from the streets into a network of manmade pipes and natural channels. When water flows across yards, streets and other surfaces, it picks up contaminants and carries the untreated runoff to a natural body of water. Dumping wastes into a storm drain or on the ground directly affects the environment, damaging potential sources of drinking and recreational waters and endangering wildlife and habitat.

Potential Stormwater Pollutants

  • Automotive fluids
  • Litter, including cigarette butts
  • Fertilizer and weed killer from yards
  • Grass clippings, leaves and other yard waste
  • Pet waste
  • Soap, paint, cleaning supplies and other household chemicals
  • Sediment from exposed ground

Stormwater pollution can …

  • Increase the risk of illness and harm to individuals, particularly children, and pets who come into contact with the water
  • Degrade the quality of water we use for drinking, irrigation, recreation and industry; which could cause increased treatment costs
  • Damage the natural ecosystems of our waterways and damage the plant and animal habitat
  • Clog storm drains with sediment and trash, requiring more maintenance and potentially cause streets to flood

How you can help

You can be a stormwater steward. That means in simple, every day activities, like bagging your pet’s waste or taking your car to a commercial wash, can help keep harmful pollutants out of our waterways.

Here is a list of every day activities you can do to help prevent stormwater pollution in our communities:

  • Use fewer lawn chemicals and don't water right away. Try using compost instead of chemical fertilizer. Don't water after applying lawn chemicals and don't apply them before a heavy rainfall is predicted.
  • Clean up after your pets. Carry disposable bags while walking your dog so you can pick up and dispose of pet waste in the trash. In your own yard, pick up pet waste, bag it and put it in the trash. Leaving it in the grass sends unsafe bacteria into the storm drains when it rains.
  • Recycle used oil. Find an oil recycling center near your home or work to properly dispose of used oil. Johnson County has more than 30 used-oil recycling sites, such as gas stations, automotive supply stores and lubrication service centers. For a list of sites, go to
  • Sweep driveways and sidewalks rather than washing them off with the hose. Remove grass clippings, dirt and other debris and dispose of it properly.
  • Use a commercial car wash to minimize the effects on the environment. If you wash your car at home, do it on the grass.
  • Use biodegradable, phosphate-free, water-based cleaners only. Use a spray nozzle to save water.
  • Properly dispose of trash and yard waste. Contact your city hall for your community's instructions for proper trash and yard waste disposal.
  • Use household products as directed. Properly store and dispose of all hazardous household products at a hazardous waste permitted facility.
  • Shop smart. Purchase and use nontoxic, biodegradable, recycled and recyclable products whenever possible.